Numerical simulation of novel polypropylene hollow fiber heat exchanger and analysis of its characteristics

Hollow fiber heat exchangers for lower temperature applications have attracted more and more attention because of their resistances to scaling and corrosion, and substantial space, cost and energy savings. It is important to study flow and heat transfer characteristics to develop the new type and promote wide application of hollow fiber heat exchangers. In this study, a three-dimensional model of tube-and-shell hollow fiber heat exchanger (there were no baffles on the shell-side) was proposed using Computational Fluid Dynamics (CFD) software tool FLUENT. The study of the hollow fiber heat exchanger used water–water system. Firstly, the impacts of velocities in tube-side and shell-side on total heat transfer coefficient were simulated. The calculated contributions of tube, shell and fiber wall heat resistances to the total resistance are 20%, 50% and 30%, respectively. Secondly, the velocity distribution in the hollow fiber heat exchanger was given, the thermal resistance of each side and the flow and heat transfer characteristics of the heat exchanger were discussed. Thirdly, the influence of packing fraction of hollow fibers to overall heat transfer coefficient was simulated. The result showed that there was an optimal value of packing fraction, which is 13–19%. The proposed method provides a significant reference for further study of hollow fiber heat exchangers.